Heretofore, tire treads of the removable type have generally been made from rubber reinforced with plies of cords either of steel or textile material. Such removable treads have been made by conventional methods in which at least one layer of rubber containing cord reinforcement has been wrapped around a building drum to form a belt after which it is placed in a mold and vulcanized.
With a cast polyurethane torus tire tread, the polyurethane can be poured or injected into a mold in a liquid state and, accordingly, there is a problem in positioning the reinforcing cords and obtaining adhesion between the polyurethane and the reinforcing cords. The cords can be wrapped around the inner core of a mold; however, reinforcing cords at that position present problems in providing the strength and wear properties which are necessary for a tread of this type. The cords may also be spaced from the inner core by spacing members interposed between the inner core and the reinforcing wire cords. This is not desirable when the liquid polyurethane is injected into the mold because these spacing members will remain in the tread and may weaken the tread or provide channels through which moisture can reach the wire cords.
Therefore, it is an object of this invention to provide a method of making a molded article having a cord reinforcement positioned therein.
Another object is to provide a method of making a cast annular, cord-reinforced tread belt for a tire, preferably of the pneumatic type in which the cord is positioned during the casting operation by a spacer which does not become a part of the tread belt.
A further object is to provide a method of making a cast tire in which reinforcing cord is positioned in and adhered to the outer tread portion in the tire mold prior to injection of the polyurethane material for the remainder of the tire.